Iuri Rocha

Iuri Rocha
Delft University of Technology | TU · Department of Structural Engineering

About

21
Publications
3,886
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341
Citations
Citations since 2016
17 Research Items
332 Citations
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2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100

Publications

Publications (21)
Preprint
Full-text available
Driven by the need to accelerate numerical simulations, the use of machine learning techniques is rapidly growing in the field of computational solid mechanics. Their application is especially advantageous in concurrent multiscale finite element analysis (FE$^2$) due to the exceedingly high computational costs often associated with it and the high...
Article
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Polymers and polymer composites are negatively impacted by environmental ageing, reducing their service lifetimes. The uncertainty of the material interaction with the environment compromises their superior strength and stiffness. Validation of new composite materials and structures often involves lengthy and expensive testing programs. Therefore,...
Article
Full-text available
Service lifetimes of polymers and polymer composites are impacted by environmental ageing. The validation of new composites and their environmental durability involves costly testing programs, thus calling for more affordable and safe alternatives, and modelling is seen as such an alternative. The state-of-the-art models are systematized in this wo...
Article
Full-text available
Concurrent multiscale finite element analysis (FE²) is a powerful approach for high-fidelity modeling of materials for which a suitable macroscopic constitutive model is not available. However, the extreme computational effort associated with computing a nested micromodel at every macroscopic integration point makes FE² prohibitive for most practic...
Preprint
Full-text available
Concurrent multiscale finite element analysis (FE2) is a powerful approach for high-fidelity modeling of materials for which a suitable macroscopic constitutive model is not available. However, the extreme computational effort associated with computing a nested micromodel at every macroscopic integration point makes FE2 prohibitive for most practic...
Article
Full-text available
Although being a popular approach for the modeling of laminated composites, mesoscale constitutive models often struggle to represent material response for arbitrary load cases. A better alternative in terms of accuracy is to use the FE² technique to upscale microscopic material behavior without loss of generality, but the associated computational...
Article
Full-text available
Accurate numerical modeling of fracture in solids is a challenging undertaking that often involves the use of computationally demanding modeling frameworks. Model Order Reduction (MOR) techniques can be used to alleviate the computational effort associated with these models. However, the traditional offline‐online reduction approach is unsuitable f...
Article
Full-text available
This work presents a reduced-order modeling framework that precludes the need for offline training and adaptively adjusts its lower-order solution space as the analysis progresses. The analysis starts with a fully-solved step and elements are clustered based on their strain response. Elements with the highest strains are solved with a local/global...
Article
Characterization of the mechanical properties of the fiber/matrix interface is a challenge that needs to be addressed to enable accurate micromechanical modeling of failure in composite materials. In this paper a numerical investigation is presented into one of the tests that has been proposed for measuring these interfacial properties. A new cohes...
Article
This paper investigates the viscoelastic/viscoplastic/fracture behavior of an epoxy resin. A state-of-the-art pressure-dependent elastoplastic constitutive model (Melro et al. 2013) is expanded to include viscoelasticity, viscoplasticity and a modified damage formulation with linear softening and shrinking pressure-dependent fracture surface. A wat...
Article
In this paper, a number of techniques used to accelerate the solution of finite element problems involving a large number of load cycles areexplored and applied to the micromechanical analysis of fiber-reinforced composites. The microscopic domain consists of unidirectional linear-elastic fibers embedded in a viscoelastic/viscoplastic polymeric mat...
Article
This work investigates hygrothermal aging degradation of unidirectional glass/epoxy composite specimens through a combination of experiments and numerical modeling. Aging is performed through immersion in demineralized water. Interlaminar shear testes are performed after multiple conditioning times and after single immersion/redrying cycles. Degrad...
Article
A combined experimental and numerical investigation is conducted on the anisotropic water diffusion behaviour of unidirectional glass/epoxy composites. Experimental diffusivity values are obtained by immersing thin material slices for each of its planes of orthotropy extracted from a thick composite panel and interphase measurements are performed u...
Article
In this work, a glass/epoxy material system applied in wind turbine blades was used to evaluate degradation processes induced by water ingression. Composite and neat epoxy specimens were conditioned in demineralised water at 50°C for 4800h and tested quasi-statically and in fatigue. Comparing results from mechanical tests in composite specimens, si...
Article
In this work, a numerical framework for modelling of hygrothermal ageing in laminated composites is proposed. The model consists of a macroscopic diffusion analysis based on Fick's second law coupled with a multiscale FE2 stress analysis in order to take microscopic degradation mechanisms into account. Macroscopic material points are modelled with...
Article
Full-text available
In this work a glass/epoxy composite commonly used in wind turbine blades is exposed to a humid environment at an elevated temperature. To research the anisotropic diffusion behaviour observed in unidirectional composite specimens, experimental results of slices cut along the three directional planes of the laminate immersed in demineralised water...
Conference Paper
Full-text available
Placas e cascas laminadas têm sido amplamente utilizadas na fabricação de componentes de aeronaves, automóveis e estruturas navais. A consideração da flambagem é de fundamental importância no projeto destas estruturas, devido a sua elevada esbeltez. Adicionalmente, o comportamento pós-crítico destas estruturas é de grande importância, visto que ele...
Article
This work presents a genetic algorithm combining two types of computational parallelization methods, resulting in a hybrid shared/distributed memory algorithm based on the island model using both Open-MP and MPI libraries. In order to take further advantage of the island configuration, different genetic parameters are used in each one, allowing the...
Article
Full-text available
This work presents a methodology for minimum weight design of laminated composite tubes. The design variables are the number of plies and the thickness and fiber orientation of each ply. The formulation includes stress and stability constraints. Multiple loading cases can be considered. A highly efficient axi-symmetric finite element formulation wa...

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